Concentrated aqueous fabric conditioning compositions are well known in the art. These compositions contain various types of cationic materials either alone or in combination with other fabric softening components (e.g. U.S. Pat. Nos. 3,681,241, Rudy et al.; 4,439,335, Burns et al.; and 4,772,404, Fox et al.).
The conventional method of preparing such dual active formulations is to combine the components and add an acid agent as a finishing step to adjust the pH of the formulas to the desired range (see in particular Fox et al., U.S. Pat. No. 772,404). In Burns, 4, 439,335, it is taught that the fabric softening compositions should have a pH of from about 5.5 to about 6.5 prepared by adding small amounts of pH adjusting agents at the end of the preparation process.
De Block et al., U.S. Pat. No. 4,999,121 describes a preparation process wherein a solution of an acid is added in two steps prior to the addition of the fabric conditioning active and after the addition of softener. The compositions predominantly contain a cyclic amine and require solubilizer compounds such as polyethylene glycol be added separately from the actives as well as mixing speed higher than state of the art processes involving conventional softening agents, and the absence of water soluble ionizable salts which he teaches "give a detrimental effect on product stability" in state of the art made compositions.
Concentrated fabric conditioners having more than about 23% of softening actives have proven almost impossible to prepare by conventional state of the art processes without encountering problems such as product gelling and instability.
The various solutions used in the art have not been entirely satisfactory for preparing such concentrates.
There is, thus, a need for concentrated compositions having more than 23% fabric conditioning active without requiring a high shearing step.
It is an object of the present invention to provide a process for making stable highly concentrated fabric conditioning compositions.
It is a further object of the present invention to simplify the process for obtaining such compositions by introducing the actives into an acidified bath.
It is a further object of the present invention to provide concentrated fabric softening compositions made according to the process of the invention.